Ground fault interrupter tester

Abstract

A hand-held ground fault interrupter for checking the operation of a ground fault protected wall receptacle. The blades of an electrical terminal protrude from one end of a housing which contains a potentiometer and electrical connecting means between the potentiometer and the blades. The tester creates a ground fault by allowing current to leak to the ground path, the amount of leakage varied by the potentiometer. A properly operating ground fault interrupter senses the leakage and is designed to trip when it sees a selected level of current leakage. Tripping at lower levels or failure to trip at higher levels indicates a defective interrupter. Recesses in the sides of the housing provide access to the potentiometer dial for rotating the dial and reading a label affixed thereto.

I claim: 
     
       1. A hand-held ground fault interrupter tester comprising: a housing,   a potentiometer contained within the housing,   electrical terminal blades mounted in the housing and protruding from one end in fixed positional relationship for insertion into a wall receptacle,   electrical connecting means between the potentiometer and terminal blades, said means permitting a potentiometer-controlled current leakage to the ground path which, upon reaching a desired level, will trip a properly functioning ground fault interrupter so that tripping at a lower level or failure to trip at higher levels will indicate a defective interrupter.   
     
     
       2. The structure of claim 1 wherein the potentiometer is of the rotary type, having a disc-shaped potentiometer dial whose rotational position variably determines the output of the potentiometer. 
     
     
       3. The structure of claim 2 wherein at least one of the edges of the potentionmeter dial protrudes through a slot in a surface of the housing, providing access for rotating the dial. 
     
     
       4. The structure of claim 3 wherein the potentiometer dial has a circular label attached to a face of the dial for indicating the level of current leakage at a particular dial setting. 
     
     
       5. The structure of claim 4 wherein the outside diameter of the label is substantially tangential to the side of the housing and the housing has a recess cut into it above the label so as to expose the label to view. 
     
     
       6. A hand-held ground fault interrupter tester according to claim 2 wherein the housing has a generally flat, elongated configuration and the potentiometer dial is mounted on a shaft located on the longitudinal midline of the tester, the dial having a diameter sufficiently larger than the housing width such that the dial edges extend through both sides of the housing. 
     
     
       7. The structure of claim 6 wherein the potentiometer dial has a circular label attached to both faces of the dial for indicating the level of current leakage at a particular dial setting, the labels having an outside diameter substantially equal to the housing width and the housing having recesses cut into it above each label so as to expose them to view. 
     
     
       8. A hand-held ground fault interrupter tester according to claim 1 which includes at least one indicator lamp which lights upon insertion of the tester into a live receptacle and goes out upon tripping of the ground fault interrupter.